There is a trend for electronic devices to increase the number or type of functions they perform and therefore increase their energy consumption. There is also a trend to decrease the size of electronic devices.
As the amount of energy stored at an electronic device is limited by its size it can be difficult to balance the need for energy consumption with the need for a small compact device.
One approach to this problem has been to make electronic devices more energy efficient.
Another approach to this problem has been to develop more efficient energy stores. This has involved the development of batteries, such as Li-ion batteries, that store greater energy per unit volume and then the replacement of Li-ion batteries by fuel cells.
It would be desirable to increase the energy available for use at an electronic device.